1. Field of the Invention
This invention relates to diagnosing internal combustion engines electronically.
2. Description of the Prior Art
One of the subsystems on a vehicle mounted engine which is critical to continuing engine health is the cooling system. In diesel engines, coolant must flow adjacent the cylinder jackets or the engine will disintegrate quite rapidly. The water temperature does not get too hot, so a very primary concern is the condition of the coolant pump; that is, is the coolant pump healthy and does it deliver a suitable mass flow rate of coolant at a suitable pressure; and another primary concern is whether the coolant passages in the engine have become restricted. The principle tests for these conditions in the prior art is measuring pressure ratios across the pump and across the engine at specific speeds while the engine-related vehicle is loaded by a dynomometer. Obviously, the use of a dynomometer is not always possible; further, dynomometers are extremely expensive and cumbersome and should be avoided if possible.